Hot Water Extraction To Pretreat Food Waste And Rhizopus Arrhizus And Aspergillus Niger Use Hydrolysate

As the output of food waste increases year by year,the actual utilization rate for its disposal is relatively low.How to deal with and use this part of resources has become a major problem that puzzles people.The composition of food waste is complex and sticky.Air entry is hindered during microbial conversion and utilization.The utilization rate of food waste is reduced,and it needs to be reused after a certain pretreatment.This article first measured the nutritional composition of food waste,it can be known that it contains 69.43%of the resources that can be used by microorganisms,heat extraction pretreatment of food waste,through single factor conditions and optimization optimization,the optimal condition:CO2 2?3 MPa,temperature 130 ?,time 60 min,solid-liquid ratio 1:3(approximately 75%-80%),reducing sugar content is 89.98 mg·g-1 dry base of the food;the concentration of liquid reducing sugar obtained by inspection is 25.37 g·L-1(Maltose 19.45 g·L-1,glucose 5.02 g·L-1,xylose 0.90 g·L-1,the concentration of the supernatant of the mixed food is increased by about 5 times.The weight loss rate of food waste is more than 50%,with certain degradation,preliminary liquid pH floats between 3.5-3.9.Then,Rhizopus arrhizus uses hydrolysate to screen strains tolerated to obtain strain RH-7#-89.The acid production is up to 5.61 g·L-1.The optimized strain is 1.72 times higher than the pre-fermentation acid production and the space-time yield is 116.88 mg·L-1 h-1 is about 70.12%of the acid produced by the basic medium at the same concentration(30 g·L-1),which is about 2.5 times that of the food waste.The hydrolysate was also fermented by Aspergillus niger(HL-5),and the hydrolysate was investigated to contain an acid metabolism metabolic component(5-hydroxymethylfurfural)of Aspergillus niger.Its presence had a relatively weak influence on the growth and development of A.niger Aspergillus niger has strong inhibition of acid production metabolism.Using activated carbon for adsorption and detoxification,the HMF content of the hydrolysate after treatment was reduced to 0.05 g·L-1,a decrease of 73.68%compared with the original,and the reducing sugar of the hydrolysate after treatment was reduced by 9.78%to 22.89 g·L-1(maltose 18.07 g·L-1,glucose 3.62 g·L-1,xylose 0.60 g·L-1).The yield of detoxified hydrolysate gluconic acid reached 15.46 g·L-1,which was 3.62 g·L-1 higher than that of untreated hydrolysate,the yield of gluconic acid increased by 22.7%,and the utilization rate of reducing sugar was 67.54%.